WO2021206378A1 - Procédé et appareil de transmission et de réception de données dans un système de communication prenant en charge de multiples liaisons - Google Patents

Procédé et appareil de transmission et de réception de données dans un système de communication prenant en charge de multiples liaisons Download PDF

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Publication number
WO2021206378A1
WO2021206378A1 PCT/KR2021/004130 KR2021004130W WO2021206378A1 WO 2021206378 A1 WO2021206378 A1 WO 2021206378A1 KR 2021004130 W KR2021004130 W KR 2021004130W WO 2021206378 A1 WO2021206378 A1 WO 2021206378A1
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Prior art keywords
link
frame
data frame
transmission
cts
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PCT/KR2021/004130
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English (en)
Korean (ko)
Inventor
황성현
강규민
박재철
오진형
임동우
최수나
김용호
홍한슬
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한국전자통신연구원
한국교통대학교산학협력단
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Priority to US17/916,406 priority Critical patent/US20230156795A1/en
Publication of WO2021206378A1 publication Critical patent/WO2021206378A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/002—Transmission of channel access control information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
    • H04W74/0816—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA] with collision avoidance
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/14—Multichannel or multilink protocols
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0866—Non-scheduled access, e.g. ALOHA using a dedicated channel for access
    • H04W74/0891—Non-scheduled access, e.g. ALOHA using a dedicated channel for access for synchronized access
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/15—Setup of multiple wireless link connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]

Definitions

  • the present invention relates to a wireless local area network (WLAN) communication technology, and more particularly, to a technology for transmitting and receiving data in a device that does not support simultaneous transmit and receive (STR).
  • WLAN wireless local area network
  • the wireless LAN technology may be a technology that enables mobile devices such as a smart phone, a smart pad, a laptop computer, a portable multimedia player, and an embedded device to wirelessly access the Internet based on a wireless communication technology in a short distance.
  • a standard using a wireless LAN technology is mainly being developed as an IEEE 802.11 standard by the Institute of Electrical and Electronics Engineers (IEEE).
  • IEEE 802.11 An early version of the IEEE 802.11 standard can support a communication rate of 1 to 2 mega bit per second (Mbps).
  • Subsequent versions of the IEEE 802.11 standard are being standardized in the direction of improving communication speed.
  • the revised version of the IEEE 802.11a standard can support a communication speed of up to 54 Mbps using Orthogonal Frequency Division Multiplexing (OFDM) in the 5 GHz band.
  • the IEEE 802.11b standard utilizes the Direct Sequence Spread Spectrum (DSSS) method to support a communication speed of up to 11Mbps in the 2.4 GHz band where the initial version operates.
  • DSSS Direct Sequence Spread Spectrum
  • the IEEE 802.11n standard supporting high throughput (HT) wireless LAN technology has been developed due to the demand for higher speed.
  • the IEEE 802.11n standard may support the OFDM scheme.
  • MIMO multiple input multiple output
  • the maximum communication speed may be improved in the 2.4 GHz band and the 5 GHz band.
  • the IEEE 802.11n standard can support a communication rate of up to 600 Mbps by using 4 spatial streams and a 40 MHz bandwidth.
  • the IEEE 802.11ac standard may be a very high throughput (VHT) wireless LAN technology supporting a high throughput of 1 Gbps (gigabit per second) or more.
  • VHT very high throughput
  • the IEEE 802.11ac standard may support downlink transmission for multiple stations by utilizing MIMO technology.
  • the IEEE 802.11ax standard has been developed to increase frequency efficiency in a dense environment.
  • a communication procedure may be performed using a multi-user (MU) orthogonal frequency division multiple access (OFDMA) technology.
  • OFDMA orthogonal frequency division multiple access
  • uplink communication may be performed using MU MIMO technology and/or OFDMA technology.
  • the IEEE 802.11be standard which is an Extreme High Throughput (EHT) wireless LAN technology.
  • the goal of the IEEE 802.11be standard may be to support high throughput of 30 Gbps.
  • the IEEE 802.11be standard may support a technique for reducing transmission delay.
  • the IEEE 802.11be standard is a more extended frequency bandwidth (eg, 320 MHz bandwidth), multi-link (Multi-link) including an operation using a multi-band (Multi-band) transmission and aggregation (aggregation) operation, It may support multiple access point (AP) transmission operation, and/or efficient retransmission operation (eg, Hybrid Automatic Repeat Request (HARQ) operation).
  • AP access point
  • HARQ Hybrid Automatic Repeat Request
  • the multi-link operation is an operation that is not defined in the existing WLAN standard, it may be necessary to define a detailed operation according to the environment in which the multi-link operation is performed.
  • simultaneous transmission and reception operations through the multi-link may not be performed due to signal interference between adjacent channels (eg, adjacent links) in one device. have.
  • a channel connection operation eg, a backoff operation
  • a transmission operation is performed in one link due to the interference. can Therefore, in the above-described situation, a method for multi-link operation may be required.
  • the technology that is the background of the invention is written to improve the understanding of the background of the invention, and may include content that is not already known to those of ordinary skill in the art to which this technology belongs.
  • STR simultaneous transmit and receive
  • a method of operating a first device includes: transmitting a first RTS frame to a second device in a first link among multiple links; receiving a first CTS frame in response to one RTS frame from the second device; when the first CTS frame is received, transmitting a first data frame to the second device in the first link; and transmitting a second RTS frame to the second device in the second link during transmission of the first data frame.
  • padding may be added to the second RTS frame so that the end time of the second RTS frame is the same as the transmission time of the first data frame.
  • padding may be added to the first data frame so that an end time of the first data frame is the same as a transmission time of the second RTS frame.
  • the method of operating the first device includes: receiving a second CTS frame from the second device in the first link and the second link after a preset period from an end time of the first data frame; transmitting a second data frame to the second device on the first link when a CTS frame is received, and transmitting a third data frame on the second link to the second device when the second CTS frame is received
  • the method may further include transmitting to the device.
  • the second CTS frame may be a response frame to the second RTS frame.
  • the reception time of the second CTS frame may be the same in the first link and the second link, and the second data frame and the third data frame may be simultaneously transmitted.
  • first data frame, the second data frame, and the third data frame may be data frames divided from one data frame.
  • the TXOP may be reset, and the length of the reset TXOP may be shorter than the length of the original TXOP.
  • the method of operating the first device may further include transmitting, in the first link and the second link, a CF-EN frame indicating early termination of the original TXOP.
  • the second device may not support the STR operation.
  • a method of operating a first device includes: transmitting a first RTS frame to a second device in a first link among multiple links; receiving a first CTS frame in response to one RTS frame from the second device; when the first CTS frame is received, transmitting a first data frame to the second device in the first link; and transmitting a second data frame to the second device in the second link without an RTS-CTS operation when a channel access operation in a second link among the multiple links is completed before the transmission time of the first data frame.
  • the transmission operation from the first device to the second device may not be performed in the period from the end time of the channel access operation to the transmission time of the second data frame.
  • the transmission time of the first data frame and the transmission time of the second data frame may be the same, and the end time of the first data frame and the end time of the second data frame may be the same.
  • the method of operating the first device may further include transmitting a CTS to self frame to the second device in the second link before transmitting the second data frame, wherein the CTS to self frame
  • a transmission time of the first data frame may be the same as a transmission time of the first data frame
  • an end time of the first data frame may be the same as an end time of the second data frame.
  • the method of operating the first device may further include transmitting a CTS to self frame to the second device in the second link before transmitting the second data frame, wherein the CTS to self frame
  • the transmission time of the first CTS frame may be the same as the reception time of the first CTS frame
  • the transmission time of the first data frame may be the same as the transmission time of the second data frame.
  • a method of operating a first device includes performing a first channel access operation in a first link among multiple links, and performing a first channel access operation in a second link among the multiple links. performing a channel access operation, and when the first channel access operation and the second channel access operation are completed, transmitting an RTS frame to a second device in the first link and the second link have.
  • the method of operating the first device includes receiving a CTS frame that is a response to the RTS frame from the second device in the first link and the second link, and when the CTS frame is received, the The method may further include transmitting a data frame to the second device in the first link and the second link, and the transmission time of the data frame in the first link and the second link may be the same.
  • the transmission operation of the RTS frame in the first link may not be performed until the completion time of the second channel access operation.
  • the transmission operation of the RTS frame in the second link may not be performed until the completion time of the first channel access operation.
  • the transmission time of the RTS frame in the first link and the second link may be the same.
  • communication between devices may be performed using a multi-link.
  • Some links (eg, some channels) among the multiple links are adjacent to each other so that a simultaneous transmit and receive (STR) operation cannot be performed, and the first station performs transmission using the first link among the multiple links.
  • the access point may not be able to transmit a frame to the second station using the second link among multiple links.
  • the transmission operation in the first link may be stopped, and the second station may transmit a response for the reception operation in the second link.
  • FIG. 1 is a block diagram illustrating a first embodiment of a communication node constituting a wireless LAN system.
  • FIG. 2 is a conceptual diagram illustrating a first embodiment of multiple links established between MLDs.
  • FIG. 3 is a flowchart illustrating a first embodiment of a negotiation procedure for a multi-link operation in a wireless LAN system.
  • 4A is a timing diagram illustrating a first embodiment of a method for accessing a channel in a wireless LAN system supporting multiple links.
  • 4B is a timing diagram illustrating a second embodiment of a method for accessing a channel in a wireless LAN system supporting multiple links.
  • 5A is a timing diagram illustrating a first embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 5B is a timing diagram illustrating a second embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 6A is a timing diagram illustrating a third embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 6B is a timing diagram illustrating a fourth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 6C is a conceptual diagram illustrating a first embodiment of a method for dividing a PPDU in a wireless LAN system supporting multiple links.
  • FIG. 7A is a timing diagram illustrating a fifth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • FIG. 7B is a timing diagram illustrating a sixth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 7C is a timing diagram illustrating a seventh embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • FIG. 8 is a conceptual diagram illustrating a second embodiment of a method for dividing a PPDU in a wireless LAN system supporting multiple links.
  • 9A is a timing diagram illustrating an eighth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 9B is a timing diagram illustrating a ninth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 10A is a timing diagram illustrating a tenth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 10B is a timing diagram illustrating an eleventh embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 11A is a timing diagram illustrating a twelfth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 11B is a timing diagram illustrating a thirteenth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • FIG. 12 is a timing diagram illustrating a fourteenth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • FIG. 13 is a timing diagram illustrating a fifteenth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • FIG. 14 is a timing diagram illustrating a 16th embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 15 is a timing diagram illustrating a 17th embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 16A is a timing diagram illustrating an eighteenth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 16B is a timing diagram illustrating a 19th embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 17 is a timing diagram illustrating a twentieth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • 18 is a timing diagram illustrating a 21st embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.
  • wireless communication system to which embodiments according to the present invention are applied will be described.
  • the wireless communication system to which the embodiments according to the present invention are applied is not limited to the content described below, and the embodiments according to the present invention can be applied to various wireless communication systems.
  • a wireless communication system may be referred to as a “wireless communication network”.
  • FIG. 1 is a block diagram illustrating a first embodiment of a communication node constituting a wireless LAN system.
  • a communication node 100 may be an access point, a station, an access point (AP) multi-link device (MLD), or a non-AP MLD.
  • An access point may mean an AP, and a station may mean an STA or a non-AP STA.
  • the operating channel width supported by the access point may be 20 MHz (megahertz), 80 MHz, 160 MHz, or the like.
  • the operating channel width supported by the station may be 20 MHz, 80 MHz, etc.
  • the communication node 100 may include at least one processor 110 , a memory 120 , and a plurality of transmission/reception devices 130 connected to a network to perform communication.
  • the transceiver 130 may be referred to as a transceiver, a radio frequency (RF) unit, an RF module, or the like.
  • the communication node 100 may further include an input interface device 140 , an output interface device 150 , a storage device 160 , and the like.
  • Each of the components included in the communication node 100 may be connected by a bus 170 to communicate with each other.
  • each of the components included in the communication node 100 may be connected through an individual interface or an individual bus centered on the processor 110 instead of the common bus 170 .
  • the processor 110 may be connected to at least one of the memory 120 , the transceiver 130 , the input interface device 140 , the output interface device 150 , and the storage device 160 through a dedicated interface. .
  • the processor 110 may execute a program command stored in at least one of the memory 120 and the storage device 160 .
  • the processor 110 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed.
  • Each of the memory 120 and the storage device 160 may be configured as at least one of a volatile storage medium and a non-volatile storage medium.
  • the memory 120 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).
  • FIG. 2 is a conceptual diagram illustrating a first embodiment of a multi-link configured between multi-link devices (MLDs).
  • MLDs multi-link devices
  • the MLD may have one medium access control (MAC) address.
  • MLD may refer to AP MLD and/or non-AP MLD.
  • the MAC address of the MLD may be used in the multi-link setup procedure between the non-AP MLD and the AP MLD.
  • the MAC address of the AP MLD may be different from the MAC address of the non-AP MLD.
  • Access point(s) associated with AP MLD may have different MAC addresses, and station(s) associated with non-AP MLD may have different MAC addresses.
  • Access points in the AP MLD having different MAC addresses may be in charge of each link and may perform the role of an independent access point (AP).
  • AP independent access point
  • Non-AP MLD may be referred to as STA MLD.
  • MLD may support simultaneous transmit and receive (STR) operation.
  • STR simultaneous transmit and receive
  • the MLD may perform a transmit operation on link 1 and may perform a receive operation on link 2 .
  • the MLD supporting the STR operation may be referred to as an STR MLD (eg, STR AP MLD, STR non-AP MLD).
  • a link may mean a channel or a band.
  • a device that does not support the STR operation may be referred to as an NSTR (non-STR) AP MLD or an NSTR non-AP MLD (or NSTR STA MLD).
  • Multi-link operation may include multi-band transmission.
  • the AP MLD may include a plurality of access points, and the plurality of access points may operate on different links. Each of the plurality of access points may perform function(s) of a lower MAC layer. Each of the plurality of access points may be referred to as a “communication node” or “sub-entity”.
  • a communication node ie, an access point
  • a non-AP MLD may include a plurality of stations, and the plurality of stations may operate on different links. Each of the plurality of stations may be referred to as a “communication node” or “sub-entity”.
  • a communication node ie, a station
  • a communication node may operate under the control of a higher layer (or the processor 110 illustrated in FIG. 1 ).
  • MLD may perform communication in multi-band. For example, MLD may perform communication using a 40 MHz bandwidth according to a channel extension method (eg, a bandwidth extension method) in a 2.4 GHz band, and communicate using a 160 MHz bandwidth according to a channel extension method in a 5 GHz band can be performed. MLD may perform communication using a 160 MHz bandwidth in a 5 GHz band, and may perform communication using a 160 MHz bandwidth in a 6 GHz band.
  • One frequency band (eg, one channel) used by the MLD may be defined as one link. Alternatively, a plurality of links may be configured in one frequency band used by the MLD.
  • the MLD may establish one link in the 2.4 GHz band and two links in the 6 GHz band. Each link may be referred to as a first link, a second link, a third link, and the like.
  • the MLD may establish multiple links by performing an access procedure and/or a negotiation procedure for multi-link operation. In this case, the number of links and/or a link to be used among multiple links may be set.
  • the non-AP MLD eg, a station
  • the non-AP MLD may check band information capable of communicating with the AP MLD.
  • the non-AP MLD may configure one or more links among links supported by the AP MLD to be used for the multi-link operation.
  • a station that does not support multi-link operation eg, an IEEE 802.11a/b/g/n/ac/ax station
  • the MLD may perform the STR operation. For example, the MLD may transmit a physical layer convergence procedure (PLCP) protocol data unit (PPDU) 1 using link 1 among multiple links, and may receive PPDU 2 using link 2 among multiple links.
  • PLCP physical layer convergence procedure
  • PPDU protocol data unit
  • IDC in-device coexistence
  • multiple links including link 1, link 2, and link 3 may be configured between the AP MLD and the non-AP MLD 1. If the band spacing between link 1 and link 3 is sufficient, AP MLD may perform STR operation using link 1 and link 3. That is, the AP MLD may transmit a frame using link 1 and may receive a frame using link 3 . If the band spacing between link 1 and link 2 is not sufficient, AP MLD may not be able to perform STR operation using link 1 and link 2. If the band spacing between link 2 and link 3 is not sufficient, AP MLD may not be able to perform STR operation using link 2 and link 3.
  • FIG. 3 is a flowchart illustrating a first embodiment of a negotiation procedure for a multi-link operation in a wireless LAN system.
  • an access procedure between a station (STA) and an access point (AP) in an infrastructure basic service set (BSS) is a probe step of the access point, and an authentication step between the station and the detected access point (authentication) step), and an association step between the station and the authenticated access point.
  • the station may detect one or more access points using a passive scanning method or an active scanning method.
  • the station may detect one or more access points by overhearing a beacon frame transmitted by the one or more access points.
  • the station may transmit a probe request frame and receive one or more access points by receiving a probe response frame that is a response to the probe request frame from one or more access points. points can be detected.
  • the station may perform an authentication step with the detected access point(s). In this case, the station may perform an authentication step with a plurality of access points.
  • An authentication algorithm according to the IEEE 802.11 standard may be classified into an open system algorithm for exchanging two authentication frames, a shared key algorithm for exchanging four authentication frames, and the like.
  • the station may transmit an authentication request frame based on an authentication algorithm according to the IEEE 802.11 standard and communicate with the access point by receiving an authentication response frame that is a response to the authentication request frame from the access point. authentication can be completed.
  • the station may perform a connection step with the access point.
  • the station may select one access point from among itself and the access point(s) that have performed the authentication step, and may perform the connection step with the selected access point. That is, the station may transmit an association request frame to the selected access point, and receive an association response frame that is a response to the association request frame from the selected access point to establish a connection with the selected access point.
  • the MLD may include one or more STAs associated with the corresponding MLD.
  • the MLD may be a logical entity.
  • MLD can be classified into AP MLD and non-AP MLD.
  • Each STA associated with the AP MLD may be an AP, and each STA associated with the non-AP MLD may be a non-AP STA.
  • a multiple link discovery procedure, a multiple link setup procedure, and the like may be performed.
  • the multi-link discovery procedure may be performed in the detection phase between the station and the access point.
  • the ML multi-link information element may be included in a beacon frame, a probe request frame, and/or a probe response frame.
  • a multi-link operation is used between an access point (eg, an AP associated with an MLD) and a station (eg, a non-AP STA associated with an MLD) in the detection phase.
  • Information indicating whether it is possible and available link information can be exchanged.
  • an access point and/or station may transmit information of a link to use for multi-link operation.
  • a negotiation procedure for multi-link operation may be performed in an access procedure (eg, a connection step) between a station and an access point, and information element(s) necessary for multi-link operation are included in an action frame in the negotiation procedure. can be set or changed by
  • an access procedure eg, a connection step
  • available link(s) of the access point may be established, and an identifier (ID) may be assigned to each link.
  • ID an identifier
  • information indicating whether each link is activated may be transmitted, and the information may be expressed using a link ID.
  • Information indicating whether multi-link operation is available may be transmitted and received in the exchange procedure of a capability information element (eg, extremely high throughput (EHT) capability information element) between the station and the access point.
  • the capability information element includes information of a supporting band, information of a supporting link (eg, ID and/or number of supporting links), information of links capable of STR operation (eg, band information of links) , interval information of links), and the like.
  • the capability information element may include information that individually indicates a link capable of STR operation.
  • FIG. 4A is a timing diagram illustrating a first embodiment of a channel access method in a wireless LAN system supporting multiple links
  • FIG. 4B is a second embodiment of a channel access method in a wireless LAN system supporting multiple links. It's a timing diagram.
  • the transmission operation in the first link and the reception operation in the second link may be simultaneously performed.
  • a transmission operation using multiple links may be implemented in an independent transmission form for each link.
  • the above-described transmission operation may be performed by a device (eg, an access point or a station) capable of supporting Simultaneous Transmit and Receive (STR).
  • a device eg, an access point or a station
  • STR Simultaneous Transmit and Receive
  • a lower layer eg, a physical (PHY) layer and/or a MAC layer
  • PHY physical
  • MAC MAC
  • the channel access operation may be a carrier sensing operation performed during Arbitration InterFrame Space (AIFS) according to data included in a frame (eg, an access category (AC) of data).
  • the carrier sensing operation may be referred to as a “channel sensing operation”. "When it is determined that the channel (eg, link) is in a busy state by the carrier sensing operation" or "When transmission of the data frame of another station is completed", the channel access operation is "carrier sensing operation in AIFS" + backoff operation".
  • the carrier sensing operation may be classified into a physical carrier sensing operation and a virtual carrier sensing operation.
  • the physical carrier sensing operation may be an energy detection (ED) operation of sensing received power in an operation channel (eg, an operation link).
  • ED energy detection
  • the virtual carrier sensing operation includes "setting operation based on the value of the length field included in the preamble of a frame (eg, PPDU to MPDU) received from another station” and “duration included in the MAC header of a frame received from another station” network allocation vector (NAV) setting operation based on the value of the field and/or the value of the TXOP field included in the preamble".
  • NAV network allocation vector
  • the NAV setting operation may be an operation of setting a parameter or a transmission prohibition period for setting a transmission prohibition period during a time when the terminal does not start transmission (ie, a time during which another terminal performs a transmission operation).
  • the transmission time may be independent of the physical channel sensing result.
  • the NAV setting operation is an operation of setting a period (eg, a busy period) in which transmission of a frame is prohibited by the value of the duration field included in the MAC header of a frame transmitted by terminals inside and/or outside the basic service set (BSS).
  • BSS basic service set
  • a transmission operation in the first link of the same device may cause interference to the second link of the same device.
  • the aforementioned interference may be in-device coexistence interference (IDC).
  • IDC in-device coexistence interference
  • a device may mean an MLD, an access point, and/or a station.
  • IDC in-device coexistence interference
  • STR operation on multiple links may not be possible.
  • a device uses two links (eg, a first link and a second link) operating in a 5 GHz band, if the distance between the links is not sufficient, the transmission operation in the first link and the second link It may not be possible for the receive operations to be performed simultaneously on the link.
  • the multi-link operation may not be implemented in an independent transmission method for each link.
  • the multi-link operation may be implemented in a Synchronized Transmission method.
  • the multi-link operation may mean “transmitting/receiving operation using multiple links”.
  • the transmission start time and/or the transmission end time of the frames transmitted in each link may be set to be the same.
  • a padding bit may be added to a frame having a short length to match the frame length.
  • a channel access operation for simultaneous transmission is performed, one primary link (eg, a first link) is established, a backoff operation is performed on a primary link (eg, a second link), and , when the channel state is idle from a specific point in time in another link (eg, secondary link) to the end time (eg, success time) of the backoff operation of the primary link” (eg, the primary link and other links) may be used to perform a transmit operation.
  • the time from a specific point in time to the end of the backoff operation of the primary link is the point coordination function (PIFS) interframe space (PIFS), distributed coordination function (DCF) interframe space (DIFS), AIFS, or the backoff operation of the primary link. It can be full time.
  • Links other than the primary link may be set as sub-links. Meanwhile, after the end of the backoff operation in the primary link, the check operation of the channel occupancy status may be performed in the secondary link for a specific time period. If the channel state of the secondary link is busy at some time within a specific time period, the device may transmit a frame using only the primary link. Alternatively, the device may perform a backoff operation on the secondary link. Alternatively, the device may perform a backoff operation on a plurality of primary links for channel access. A plurality of primary links may be established, and a backoff operation may be performed on the plurality of primary links. In this case, the time interval ( Hereinafter, when the channel state of the sub-link is in an idle state during a "specific time period"), the device may perform a transmission operation using a plurality of links.
  • a frame (eg, data) transmitted in a simultaneous transmission scheme may include information on links used for simultaneous transmission.
  • Information (eg, link ID, etc.) of links used for simultaneous transmission is EHT (extremely high throughput) SIG (signal) including signal information of IEEE 802.11be in the preamble of a Physical-layer Protocol Data Unit (PPDU).
  • EHT extreme high throughput
  • SIG signal
  • PPDU Physical-layer Protocol Data Unit
  • information (eg, link ID, etc.) of links used for simultaneous transmission may be indicated by the EHT control field included in the frame.
  • the access point may set the start times of transmission operations to the station(s) to be unequal, and may perform the corresponding transmission operation.
  • the station eg, non-STR STA
  • the station incapable of STR operation should transmit a response (eg, acknowledgment (ACK)) to the frame received from the access point.
  • ACK acknowledgment
  • the end time of transmission operations in multiple links may be set to be the same.
  • the above-described operation may be referred to as a “semi-synchronized multi-link operation”.
  • FIG. 5A is a timing diagram illustrating a first embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links
  • FIG. 5B is a second embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links. It is a timing diagram showing an example.
  • a similar synchronous multi-link operation may be performed in conjunction with a request to send (RTS)-clear to send (CTS) operation.
  • RTS request to send
  • CTS clear to send
  • a station eg, STA MLD
  • STA MLD may not support STR operation.
  • a station may mean "STA MLD” or "STA associated with STA MLD”
  • an access point may mean "AP MLD” or "AP associated with AP MLD”.
  • the access point may acquire a transmit opportunity (TXOP) by performing an RTS-CTS operation on the first link.
  • the RTS-CTS operation may include "a transmission/reception operation of an RTS frame and a transmission/reception operation of a CTS frame".
  • a channel contention operation (eg, a channel access operation) on the second link may be completed.
  • the access point may transmit the RTS frame on the second link. Since the station does not support the STR operation, it may not be able to transmit the CTS frame, which is a response to the RTS frame, on the second link. When the station transmits a CTS frame in the second link, the CTS frame may cause interference in the first link.
  • a reception error for a data frame may occur in the first link.
  • the access point may support the STR operation. Accordingly, the access point may perform a sensing operation and/or a reception operation in another link while performing a transmission operation in one link.
  • a station may perform a communication operation in one link, and then may perform a communication operation in multiple links. For example, if the channel contention operation is completed in the second link while the transmission operation is performed in the first link, the station may adjust the transmission end time of the frame in the first link to match the transmission end time of the RTS frame in the second link. have. In order to align the transmission end time in multiple links, the following operation(s) may be performed.
  • the access point may align the transmission end time in multiple links by adjusting the length of the PPDU in the first link to be shorter.
  • the access point may align the transmission end time in multiple links by adding padding to the PPDU according to operation 1.
  • the access point may align the transmission end time in multiple links by adding padding to the RTS frame in the second link.
  • the transmission end time may not be aligned in a short time of OFDM symbol unit within a specific period.
  • FIG. 6A is a timing diagram illustrating a third embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links
  • FIG. 6B is a fourth embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links. It is a timing diagram illustrating an example
  • FIG. 6C is a conceptual diagram illustrating a first embodiment of a PPDU segmentation method in a WLAN system supporting multiple links.
  • one PPDU may be segmented into a plurality of PPDU parts. For example, one PPDU may be divided into PPDU part 1 and PPDU part 2, PPDU part 1 may be transmitted on a first link, and PPDU part 2 may be transmitted on a second link.
  • the access point may divide the PPDU into a plurality of PPDUs, segmented) PPDUs may be transmitted using the first link and the second link.
  • the remaining PPDU at the time when the channel access operation is successful in the second link may be divided into a plurality of PPDUs.
  • Padding eg, padding bit and/or padding symbol
  • the transmission end times of the divided PPDUs eg, PPDU part 1 and PPDU part 2 are the same.
  • the length of the padding added to each of the PPDU part 1 and the PPDU part 2 may be different from each other.
  • the transmission operation may not be performed.
  • a block ACK (BA) frame for PPDU part 1 and PPDU part 2 is received, the access point may end the TXOP by transmitting a contention free (CF)-END frame on each of the first link and the second link.
  • the duration field included in the BA frame may indicate the length of the TXOP changed according to the split transmission of the PPDU. In this case, the duration field may indicate until the time point at which the BA frame is transmitted, and the TXOP may be terminated early at the end time point of the BA frame.
  • the TXOP may not end prematurely.
  • the access point may transmit an additional PPDU (eg, another packet) within the TXOP.
  • the additional PPDU may be transmitted after SIFS from the reception time of the BA frame.
  • the duration field included in the BA frame may indicate the end time of the existing TXOP (eg, the end time of the TXOP indicated by the RTS frame).
  • a transmission operation of another packet may be performed by sharing an initial TXOP (eg, an original TXOP).
  • the TXOP may be terminated early.
  • the access point may end the TXOP by sending a CF-END frame.
  • the duration field included in the BA frame for the additional PPDU may indicate a transmission end time of the additional PPDU.
  • the TXOP sharing operation may be performed when some sections in the initial TXOP remain.
  • the remaining period in the initial TXOP may be used for the transmission operation of another station.
  • the remaining section in the TXOP may mean a TXOP sharing section.
  • Other stations cannot perform the transmission operation due to the setting of the NAV, but may perform the reception operation. Accordingly, another station may receive the frame in the TXOP sharing period (eg, the remaining period in the initial TXOP).
  • another station may perform an uplink transmission operation in the TXOP sharing interval.
  • the trigger frame may be transmitted/received after SIFS from the transmission time of the BA frame.
  • a trigger variant MU-RTS frame may be transmitted.
  • Another station that has received the MU-RTS frame may omit transmission of the CTS frame and may transmit the data frame after SIFS.
  • the trigger frame may be a frame that allocates radio resources (eg, time and/or frequency) to initiate transmission of another station, and may indicate transmission of one station.
  • a station performing an uplink transmission operation may be a station transmitting a BA frame, and when TXOP remains, the station may transmit a BA frame including data (eg, a packet) when transmitting the BA frame. have.
  • FIG. 7A is a timing diagram illustrating a fifth embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links
  • FIG. 7B is a sixth embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links. It is a timing diagram illustrating an example
  • FIG. 7C is a timing diagram illustrating a seventh embodiment of a method of transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • one PPDU may be divided into a plurality of PPDU parts, and the plurality of PPDU parts may be transmitted in multiple links.
  • the access point may divide the PPDU into a plurality of PPDUs, and the divided PPDU can be transmitted using the first link and the second link.
  • the access point may transmit a CTS-to-Self frame in the second link.
  • the CTS-to-Self frame may be a control frame including a receiver address.
  • the recipient address of the CTS-to-Self frame may be set to itself (eg, an access point).
  • the station may receive the CTS-to-Self frame from the access point, may set the NAV based on the CTS-to-Self frame, and may not perform a transmission operation in the period in which the NAV is set.
  • the CTS-to-Self frame may be a control frame that is transmitted before the split transmission of the PPDU is performed.
  • the recipient address of the CTS-to-Self frame transmitted from the access point may be set to the station.
  • the duration field included in the CTS-to-Self frame may indicate the end time of the TXOP (eg, initial TXOP, original TXOP).
  • the station may receive the CTS-to-Self frame from the access point, and may determine that the split transmission of the PPDU is performed after the SIFS from the reception time of the CTS-to-Self frame.
  • the station may perform a preparation operation of buffer management for combining PPDU parts received in the first link and the second link during SIFS.
  • the PPDU transmitted in the first link may be divided according to the transmission end time of the CTS-to-Self frame.
  • the remaining PPDU may be divided into a PPDU part 1 and a PPDU part 2.
  • the access point may transmit PPDU part 1 after SIFS from the end time of the PPDU in the first link, and may transmit PPDU part 2 after SIFS from the end time of the CTS-to-Self frame in the second link.
  • the length of the TXOP may be adjusted based on a value indicated by the duration field included in the CTS-to-Self frame.
  • a time for transmitting one PPDU through the first link may be longer than a time for transmitting the divided PPDUs through the first link and the second link.
  • the raw TXOP set in the RTS frame may be adjusted to a value indicated in the duration field of the CTS-to-Self frame, and the duration field included in the MAC header of the PPDU (eg, PPDU part 1) divided in the first link is also may have the same adjusted value.
  • the length of the TXOP may be adjusted based on the duration for PPDU part 1 and PPDU part 2. In the embodiment shown in FIG.
  • the fragmented transmission of the PPDU may be terminated early.
  • the duration field of the CTS-to-Self frame and the duration field included in the MAC header of the divided PPDU may indicate the end time of the original TXOP, and the MAC of the BA frame
  • the duration field included in the header may indicate an adjusted TXOP time (eg, reduced TXOP, modified TXOP). Based on the above-described setting, the adjustment operation of the TXOP may be performed.
  • the TXOP may be adjusted by transmitting the CF-END frame, and accordingly, the TXOP may be terminated early.
  • the remaining period in the TXOP may be used for transmission of another PPDU. That is, the TXOP may be shared.
  • the length of the TXOP may be set in consideration of the transmission time of another PPDU.
  • the end time of the TXOP may be indicated by the duration field included in the MAC header of the frame, and the corresponding TXOP may be terminated early based on the value indicated by the BA frame. Alternatively, the TXOP may be terminated by transmitting a CF-END frame.
  • the PPDU may be divided into three PPDU parts, and the PPDU part having the shortest length among the three PPDU parts may be transmitted instead of the CTS-to-Self frame.
  • the PPDU part having the shortest length may perform the function of the CTS-to-Self frame.
  • the access point may succeed in the channel access operation on the second link while performing the transmission operation on the first link.
  • the access point may divide the PPDU into PPDU part 1 and PPDU part 2, may transmit PPDU part 1 in the first link, and may transmit PPDU part 2 in the second link.
  • PPDU part 2 may be transmitted after the end of the CTS-to-Self frame.
  • the CTS-to-Self frame may include information indicating a transmission time in the second link.
  • padding can be added to the PPDU that is terminated early in one link until the transmission end time of the PPDU in the other link in order to match the transmission end time of the PPDU divided for each link. have.
  • a dummy signal may be transmitted from one link to the end of the PPDU transmission after the transmission of the PPDU ended early in the other link. According to the above-described operation, transmissions in both links can be terminated at the same time. By extending the OFDM signal, the same effect as the transmission of the dummy signal can be generated.
  • the TXOP sharing operation may be performed when some sections within the initial TXOP (eg, raw TXOP) remain.
  • the remaining section in the initial TXOP may be used for a transmission operation (eg, a downlink transmission operation) of another station.
  • Other stations cannot perform a transmission operation due to the NAV setting, but may perform a reception operation. Accordingly, another station may receive the frame in the TXOP sharing period (eg, the remaining period in the initial TXOP).
  • another station may perform an uplink transmission operation in the TXOP sharing interval.
  • a trigger frame indicating that a certain terminal transmits using a certain radio resource may be transmitted/received after SIFS from the transmission time of the BA frame.
  • the BA frame may include a trigger frame.
  • the trigger frame may be a basic trigger frame.
  • a trigger frame such as an MU-RTS frame may be transmitted.
  • the trigger frame may be a control frame for indicating a time point and resources at which a single or a plurality of stations can transmit.
  • the trigger frame may serve to indicate a transmission time when a single station is designated.
  • the MU-RTS frame may be used to indicate a transmission time of direct communication between terminals.
  • a station that receives the MU-RTS frame and participates in direct communication between terminals eg, a station designated in MU-RTS
  • may omit the CTS transmission, and data after the SIFS time from the reception point of the MU-RTS frame. frame can be transmitted.
  • the recipient address of the data frame may be another station rather than an access point.
  • FIG. 8 is a conceptual diagram illustrating a second embodiment of a method for dividing a PPDU in a wireless LAN system supporting multiple links.
  • an aggregate-MAC protocol data unit may include a plurality of MPDUs. Therefore, the length of the A-MPDU may be long.
  • the MPDU is split in the A-MPDU split procedure, the original MPDU may not be restored.
  • the division unit is large, a lot of padding may be required.
  • the division unit is n codewords, the A-MPDU can be efficiently divided.
  • n may be a positive integer.
  • each of the fragmented A-MPDUs may include three codewords, and padding may be added to the fragmented A-MPDU.
  • a channel coding operation eg, a low density parity check (LDPC) operation
  • LDPC low density parity check
  • the fragmented A-MPDUs may be concatenated, and one PHY preamble may be added to the concatenated A-MPDUs.
  • a modulation symbol of the concatenated A-MPDU may be mapped to a resource, and a null signal may be mapped to the remaining resource. Alternatively, the modulation symbol corresponding to 1 may be mapped to the remaining resources.
  • FIG. 9A is a timing diagram illustrating an eighth embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links
  • FIG. 9B is a ninth embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links. It is a timing diagram showing an example.
  • the access point when "the channel state of the first link is idle and the channel state of the second link is busy", the access point transmits an RTS frame in the first link. It can transmit and receive a CTS frame, which is a response to the RTS frame, from the station in the first link. Thereafter, the access point may transmit the PPDU on the first link. During transmission of the PPDU on the first link, the channel access operation on the second link may succeed. That is, the channel state of the second link may be an idle state. In this case, in order to perform communication on the second link, the access point may transmit an RTS frame, a CTS-to-Self frame, or a divided PPDU.
  • each of the RTS frame, the CTS-to-Self frame, and the divided PPDU may be referred to as a reserved frame.
  • the access point may add padding to the divided PPDU.
  • the end time of the PPDU divided in the first link may be aligned with the end time of the reserved frame (eg, RTS frame, CTS-to-Self frame, or divided PPDU) in the second link.
  • the reserved frame eg, RTS frame, CTS-to-Self frame, or divided PPDU
  • the following two methods may be used.
  • padding may be added to the fragmented PPDU of the first link to match the end time of the reserved frame transmitted on the second link.
  • padding may be added to the reserved frame of the second link in order to match the end time of the fragmented PPDU transmitted in the first link.
  • the access point may divide the PPDU in consideration of the end time of the reserved frame.
  • the PPDU may be divided before the end of the reserved frame.
  • a PPDU (eg, A-MPDU) may be divided into decodable units.
  • the A-MPDU may be divided into units of n codewords.
  • the corresponding A-MPDU may be divided in units of MPDUs.
  • padding may be added to the segmented A-MPDU.
  • the padding may be a specific value or a specific modulation symbol.
  • padding may be added to the reserved frame to match the end time.
  • Padding may be added to a reserved frame in the MAC layer.
  • the padding may be a padding bit indicating 1 or a padding symbol.
  • the remaining PPDUs (eg, reserved PPDUs) after the transmission end time is matched may be transmitted by dividing the first link and the second link.
  • the transmission end time of the remaining PPDU can be matched equally by adding padding.
  • the remaining PPDU may be transmitted after the SIFS time.
  • FIG. 10A is a timing diagram illustrating a tenth embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links
  • FIG. 10B is an eleventh embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links. It is a timing diagram showing an example.
  • the access point may transmit an RTS frame in the first link, and A CTS frame, which is a response to the RTS frame, may be received from the station in the link. Thereafter, the access point may transmit a PPDU (eg, a fragmented PPDU) on the first link.
  • a PPDU eg, a fragmented PPDU
  • the channel access operation on the second link may succeed. That is, the channel state of the second link may be an idle state.
  • the access point may transmit an RTS frame in the second link.
  • the access point may add padding to the RTS frame.
  • the station may receive the RTS frame from the access point on the second link, and may transmit the CTS frame after SIFS from the end point of the RTS frame (eg, RTS frame + padding).
  • the CTS frame may be transmitted at the same time in the first link and the second link.
  • the access point may receive a CTS frame from the station in the first link and the second link, and may transmit a PPDU (eg, a divided PPDU) to the station in the first link and the second link.
  • the transmission time of the PPDU in the first link and the second link may be the same.
  • the end time of the split PPDU in the first link may not be the same as the end time of the RTS frame in the second link. That is, the access point may not perform the operation of matching the end time of the split PPDU in the first link and the end time of the RTS frame in the second link.
  • the station may receive the fragmented PPDU from the access point on the first link, and transmit a CTS frame (eg, a response to the RTS frame received on the second link) after SIFS from the end time of the fragmented PPDU. .
  • the CTS frame may be transmitted at the same time in the first link and the second link.
  • the station may transmit the CTS frame after "end time of RTS frame + SIFS + T1" in the second link.
  • T1 may be a difference between the end time of the split PPDU in the first link and the end time of the RTS frame in the second link.
  • T1 may be a time corresponding to padding added to the PPDU divided in the first link.
  • the CTS frame may be transmitted after “PPDU end time + SIFS + T2”.
  • T2 may be a difference between the end time of the split PPDU in the first link and the end time of the RTS frame in the second link.
  • T2 may be a time corresponding to the padding added to the RTS frame in the second link.
  • SIFS + (T1 or T2) ⁇ PIFS T1 or T2 may be set.
  • Each of T1 and T2 may be within 1 OFDM symbol time or within 4 us.
  • the access point may receive a CTS frame from the station in the first link and the second link, and may transmit a PPDU (eg, a divided PPDU) to the station in the first link and the second link.
  • the transmission time of the PPDU in the first link and the second link may be the same.
  • the station may transmit the CTS frame without receiving the RTS frame.
  • the transmission operation of the CTS frame without reception of the RTS frame may be performed based on the following method 1 or method 2.
  • the access point may generate an RTS frame including a link ID indicating a link transmitting the CTS frame, and may transmit the RTS frame in the second link.
  • the link ID included in the RTS frame may indicate “first link” or “first link and second link”.
  • the station may receive the RTS frame from the access point on the second link, and may identify link(s) through which the CTS frame will be transmitted based on the link ID included in the RTS frame.
  • the station can transmit the CTS frame simultaneously on the first link and the second link (e.g., link(s) indicated by the RTS frame) after SIFS from the end point of the RTS frame (e.g., RTS frame + padding) have.
  • the RTS frame may be an MU-RTS frame.
  • the RTS frame may further include a link ID.
  • the station receives an RTS frame from an access point included in the same AP MLD that includes the access point of the first link on a second link during reception of a frame (eg, PPDU) from an access point on a first link can do. In this case, if the channel state of the second link is in the idle state, the station may simultaneously transmit the CTS frame in the first link and the second link after SIFS from the time when the reception of the PPDU in the first link is terminated.
  • a frame e.g., PPDU
  • FIG. 11A is a timing diagram illustrating a twelfth embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links
  • FIG. 11B is a thirteenth embodiment of a method for transmitting and receiving data frames in a wireless LAN system supporting multiple links. It is a timing diagram showing an example.
  • a TXOP may be reallocated for transmission of an additional PPDU.
  • the access point may transmit an RTS frame in the second link while transmitting the PPDU in the first link.
  • the RTS frame may be transmitted when a channel contention operation (eg, a channel access operation) is completed in the second link.
  • the end time of the PPDU in the first link and the end time of the RTS frame in the second link may be set to be the same.
  • the station may receive a PPDU from the access point on a first link and an RTS frame from the access point on a second link.
  • the station may transmit a CTS frame to the access point in response to the RTS frame.
  • the CTS frame may be transmitted in the first link and the second link.
  • the CTS frame can be transmitted simultaneously on multiple links.
  • the end time of the TXOP in the multi-link may be the same as the end time of the TXOP in the first link.
  • the end time of TXOP in multiple links may be reset.
  • the end time of the TXOP in the multi-link may be earlier than the end time of the TXOP in the first link.
  • a TXOP reacquisition operation may be performed in multiple links.
  • the access point may transmit the remaining data by performing a multi-link operation. In multiple links (eg, the first link and the second link), the transmission end time may be set to be the same.
  • the access point may receive data remaining in the multi-link, and may transmit an ACK frame for the remaining data by performing the multi-link operation.
  • the transmission/reception operation of the frame using the multi-link may be completed before the end time of the TXOP in the first link.
  • the access point may return the remaining TXOP by transmitting the CF-END frame. That is, the TXOP may be terminated early.
  • a remaining section may occur in the TXOP.
  • the remaining section may be a section in which a frame transmission/reception operation is not performed.
  • the access point may transmit an RTS frame including information indicating reduced (reduced) TXOP in the second link.
  • the station may receive the RTS frame from the access point, and may confirm that the TXOP is reduced based on information included in the RTS frame.
  • the station may transmit a CTS frame to the access point in response to the RTS frame.
  • the CTS frame may be transmitted in the first link and the second link.
  • the station may transmit the CTS frame in the first link. That is, the CTS frame may not be transmitted on the second link.
  • the channel state of the second link may be determined as a busy state by a hidden node.
  • multi-link transmission (eg, reduced TXOP) may be canceled. Accordingly, the access point may transmit the remaining PPDU to the station using only the first link without using the second link.
  • the transmission/reception operation of the PPDU within the TXOP may not be completed. For example, for the PPDU transmission/reception operation, "remaining interval in TXOP + transmission/reception interval of CTS frame + 2 SIFS" may be required. That is, "transmission/reception period of CTS frame + 2 SIFS" may be further required.
  • PPDU part 1 among the remaining PPDUs may be transmitted in the TXOP, and the remaining PPDU part 2 among the remaining PPDUs may be transmitted by performing a channel contention operation.
  • the TXOP may be extended in consideration of the remaining PPDU transmission time.
  • FIG. 12 is a timing diagram illustrating a fourteenth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • additional data may be transmitted by sharing the remaining TXOP.
  • the access point may transmit an RTS frame in the second link while transmitting the PPDU in the first link.
  • the RTS frame may be transmitted when a channel contention operation (eg, a channel access operation) is completed in the second link.
  • the end time of the PPDU in the first link and the end time of the RTS frame in the second link may be set to be the same.
  • the station may receive a PPDU from the access point on a first link and an RTS frame from the access point on a second link. When the channel states of the first link and the second link are idle, the station may transmit a CTS frame to the access point in response to the RTS frame.
  • the CTS frame may be transmitted in the first link and the second link.
  • the CTS frame can be transmitted simultaneously on multiple links.
  • the remaining PPDU may be transmitted using multiple links.
  • the end time of the transmission/reception operation of the remaining PPDU may be earlier than the end time of the original TXOP. That is, a remaining section may occur in the original TXOP.
  • a communication node eg, an access point, a station
  • the remaining section in TXOP may be used by the station.
  • the station may set the end time of the transmission operation in the transmission step of the CTS frame and/or the BA frame as the end time of the original TXOP.
  • the station may set the more data field included in the MAC header (eg, QoS Data MAC header) of the BA frame to 1 .
  • the station may transmit data (eg, additional PPDU) after SIFS from the transmission end time of the BA frame.
  • the station may configure the BA frame and the additional PPDU as one A-MPDU, and may transmit a PPDU including one A-MPDU.
  • the remaining section in the TXOP may be used by the access point.
  • the access point may set the end time of the transmission operation as the end time of the original TXOP in the transmission step of the RTS frame.
  • the access point may transmit an additional PPDU to the station or another station after the SIFS from the reception end time of the BA frame.
  • the access point may trigger the uplink transmission operation of the station(s) by transmitting the trigger frame after SIFS from the reception end time of the BA frame.
  • FIG. 13 is a timing diagram illustrating a fifteenth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • RTS frames may be simultaneously transmitted for data transmission in multiple links.
  • the RTS frame When the remaining busy time in the second link is short when the channel access operation is successful in the first link, the RTS frame may be simultaneously transmitted in multiple links. The remaining busy time may be checked based on the value of the duration field included in the header of the frame. When “remaining busy time ⁇ remaining backoff time + transmission time of RTS frame" is satisfied, RTS frames may be transmitted simultaneously. If “the above conditions are satisfied and the channel access operation is successfully completed in the first link", the access point may wait without transmitting an RTS frame in the first link until the channel access operation in the second link is completed . When the channel access operation in the second link is successfully completed, the access point may simultaneously transmit the RTS frame in the first link and the second link.
  • FIG. 14 is a timing diagram illustrating a 16th embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • the access point may successfully complete the channel access operation in the first link.
  • the access point may transmit the RTS frame in the first link.
  • the access point may perform a channel access operation on the second link.
  • the channel access operation in the second link may be completed before the transmission time of the RTS frame in the first link.
  • the access point may wait for transmission of the RTS frame in the second link, and may simultaneously transmit the RTS frame in the first link and the second link when the channel access operation is completed in the first link.
  • 15 is a timing diagram illustrating a 17th embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • the access point may successfully complete the channel access operation in the first link.
  • the access point may transmit the RTS frame in the first link.
  • the access point may perform a channel access operation on the second link.
  • the channel access operation in the second link may be completed before the transmission time of the CTS frame in the first link.
  • the access point may wait for transmission in the second link, and may transmit the CTS-to-Self frame through the second link at the time of transmission of the CTS frame in the first link.
  • the transmission time of the CTS frame in the first link may be the same as the transmission time of the CTS-to-Self frame in the second link.
  • the access point may receive a CTS frame from the station on the first link.
  • the access point may simultaneously transmit data (eg, PPDU) in the first link and the second link after SIFS from the reception end time of the CTS frame.
  • data eg, PPDU
  • FIG. 16A is a timing diagram illustrating an eighteenth embodiment of a method for transmitting and receiving a data frame in a WLAN system supporting multiple links
  • FIG. 16B is a nineteenth embodiment of a method for transmitting and receiving a data frame in a WLAN system supporting multiple links. It is a timing diagram showing an example.
  • the access point may successfully complete the channel access operation in the first link.
  • the access point may transmit the RTS frame in the first link.
  • the access point may perform a channel access operation on the second link.
  • the channel access operation in the second link may be completed between the transmission time of the CTS frame and the transmission time of the data frame (eg, PPDU) in the first link.
  • the access point may wait for transmission in the second link, and may transmit the data frame through the second link at the time of transmission of the data frame in the first link.
  • the data frame transmission operation in the second link may be performed based on the following method 1 or method 2.
  • the data frame transmitted in the second link may be a Non-HT (High Throughput) PPDU having a legacy preamble.
  • the coding operation for the legacy preamble may be performed using the lowest MCS. Therefore, the transmission of the legacy frame can cover a wide area, and the station(s) can set the NAV by receiving the legacy frame.
  • the access point may transmit a CTS-to-Self frame in the second link, and may transmit a PPDU according to IEEE 802.11be after SIFS from a transmission time of the CTS-to-Self frame.
  • the CTS-to-Self frame may include a legacy preamble, and the station(s) may set the NAV by receiving the CTS-to-Self frame.
  • 17 is a timing diagram illustrating a twentieth embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • the access point may successfully complete the channel access operation in the first link.
  • the access point may transmit the RTS frame in the first link, and may receive the CTS frame from the station in response to the RTS frame.
  • the access point may transmit the data frame to the station on the first link.
  • the access point may perform a channel access operation on the second link.
  • the channel access operation in the second link may be completed after the transmission time of the data frame in the first link.
  • the access point may transmit the data frame without performing the RTS-CTS operation in the second link.
  • the data frame transmitted in the second link may be a Non-HT PPDU or a PPDU according to IEEE 802.11be.
  • 18 is a timing diagram illustrating a 21st embodiment of a method for transmitting and receiving a data frame in a wireless LAN system supporting multiple links.
  • the access point may successfully complete the channel access operation in the first link.
  • the access point may transmit the RTS frame in the first link, and may receive the CTS frame from the station in response to the RTS frame.
  • the access point may transmit the data frame to the station on the first link.
  • the access point may perform a channel access operation on the second link.
  • the access point may operate depending on the ED (energy detection) operation when the end point of the busy state in the second link is not known. Accordingly, the access point may perform the channel access operation after EIFS (or PIFS) from the end of the busy state in the second link.
  • EIFS may be longer than PIFS or AIFS.
  • the EIFS may be used to ensure the transmission/reception operation of the data frame.
  • the access point may transmit the data frame in the second link.
  • the data frame transmitted in the second link may be a Non-HT PPDU or a PPDU according to IEEE 802.11be.
  • the methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium.
  • the computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination.
  • the program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.
  • Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like.
  • Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like.
  • the hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Procédé et appareil de transmission et de réception de données dans un système de communication prenant en charge de multiples liaisons. Un procédé de fonctionnement d'un premier dispositif comprend les étapes consistant à : transmettre, dans une première liaison parmi de multiples liaisons, une première trame RTS à un second dispositif ; recevoir, en provenance du second dispositif dans la première liaison, une première trame CTS qui est une réponse à la première trame RTS ; lorsque la première trame CTS est reçue, transmettre, dans la première liaison, une première trame de données au second dispositif ; et transmettre, dans une seconde liaison pendant la transmission de la première trame de données, une seconde trame RTS au second dispositif.
PCT/KR2021/004130 2020-04-07 2021-04-02 Procédé et appareil de transmission et de réception de données dans un système de communication prenant en charge de multiples liaisons WO2021206378A1 (fr)

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